Cataclysm (Dragonlance)

In the Dragonlance books, the Cataclysm (Great Destruction) was a catastrophic event that occurred when the Kingpriest of Istar demanded to be given godlike powers in order to eliminate evil from the world.

Detailed in the novel Chosen of the Gods, Beldinas Pilofiro, last Kingpriest of Istar, never liked the concept of balance. He believed that Paladine accepted it in a time when he was previously weak. As time passed, and the forces of good flourished after the Third Dragon War in which Huma Dragonbane defeated Takhisis, he thought the time to break that outdated pact was nearing.

His decision to end the balance became strengthened when the previous Kingpriest, known as Kurnos the Ursurper, sent Sathira, an evil spirit, to kill him. Ilista, First Daughter and the woman who traveled from far Istar led by a prophecy to find the true Kingpriest, sacrificed herself in order to save him.

Though at the beginning Beldinas only fought evil, as time passed, he began to include those who did not think exactly like him. Thus, he destroyed temples and expelled followers of the Neutral Gods, as well. With time, his obsession drove him to also destroy even "heretic" followers of the Gods of Light. As detailed in the novel Divine Hammer, this also caused the Kingpriest to try to destroy all Wizards of High Sorcery, causing the Order to destroy the Towers of High Sorcery in Losarcum and Daltigoth in self-defense. This also caused Andras Rannoch, who was being mind-controlled by Fistandantilus, to curse the Tower of High Sorcery in Palanthas upon his death.

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Wikipedia